Vibration actuator, rotational drive device, and imaging device

Abstract

To reduce lateral sliding of a driven member to a vibrator in a vibrating actuator.SOLUTION: In a vibrating actuator 100, a vibrator 101 with a projection part 102a in which vibration is excited by a piezoelectric element 103 and a contact member 121 with a contact surface 121s which the projection part contacts relatively rotate around a first axis P. In the vibrating actuator, the vibrator and the contact surface are arranged in a direction parallel to the first axis. The vibration is excited by the vibrator, thereby a driving force F2 in a first direction where a tangent of a circle formed around the first axis extends between the projection part and the contact surface is generated. One of the vibrator and the contact surface is arranged inclined around a second axis T parallel to the first direction with respect to the other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vibration actuator used in a rotary drive device or the like. [Background technology]

[0002] A rotary drive device that uses a vibration actuator that excites vibration in a vibrating body using a piezoelectric element and rotationally drives a driven member that is in contact with the vibrating body is disclosed in Patent Document 1. In the rotary drive device of Patent Document 1, the vibrating body is brought into pressure contact with the driven member in a direction parallel to the central axis of rotation, and the elliptical motion of the protrusions of the vibrating body is transmitted to the driven member, thereby rotationally driving the driven member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-158054 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the rotary drive device of Patent Document 1, the vibrator generates a driving force in the tangential direction of a circle centered on the central axis of rotation (i.e., the protrusions move elliptically within a plane including the same direction), while the driven member rotates while sliding sideways in a direction different from the direction in which the driving force is generated. As a result, wear of the vibrator (protrusions) that come into pressure contact with the driven member increases, shortening the life of the device and causing wear debris to be generated.

[0005] The present invention provides a vibration actuator that can reduce the lateral slip of a driven member relative to a vibrating body, and a rotary drive device using the same. [Means for solving the problem]

[0006] A vibration actuator according to one aspect of the present invention comprises: Plate portion and a portion protruding out of the surface of the plate portion protrusion An elastic body having a contact member having a contact surface with which the protrusion comes into contact; but Rotate relative to each other about a first axis The vibration actuator is provided with a positioning member that holds the vibrator in a position tilted at a predetermined angle with respect to a contact surface, the contact surface is flat, and the vibrator and the contact surface are arranged in a direction parallel to the first axis. The positioning member has a cross-sectional shape along the first axial direction in which the thickness differs between the center side and the outer periphery side of the first axis. A rotary drive device using the vibration actuator and an imaging device using the rotary drive device also constitute other aspects of the present invention. [Effects of the Invention]

[0007] According to the present invention, it is possible to reduce the lateral slip of the driven member relative to the vibrating body in the vibration actuator. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of a vibration type motor according to a first embodiment. [Figure 2] 1A to 1C are a perspective view, a plan view, and a side view showing the appearance of a vibration type motor of a first embodiment. [Figure 3] FIG. 1 is an exploded perspective view of a rotary drive device using a vibration type motor according to a first embodiment. [Figure 4] 3A to 3C are diagrams illustrating the principle of generation of a driving force due to vibration of a vibrating body in the first embodiment. [Figure 5] Plan view and cross-sectional view illustrating skidding. [Figure 6] FIG. 10 is a diagram showing a vibration type motor in which skidding does not occur. [Figure 7] FIG. 3 is a diagram showing the relationship between a vibrating body and a friction surface in the first embodiment. [Figure 8] FIG. 2 is a perspective view showing a small base in the first embodiment. [Figure 9] Cross-sectional view taken along line FF in Figure 2. [Figure 10] FIG. 10 is a cross-sectional view of a vibration type motor according to a second embodiment. [Figure 11] FIG. 10 is a cross-sectional view of a vibration type motor according to a third embodiment. [Figure 12] FIG. 10 is a diagram showing a detailed shape of a vibrating body in Example 4. [Figure 13] 10A and 10B are diagrams illustrating the postures of the vibrating body in the first embodiment and the vibrating body in the fourth embodiment. [Figure 14]FIG. 3 is a diagram showing a contact area between a vibrating body and a friction member in the first embodiment. [Figure 15] FIG. 10 is another view showing the contact area between the vibrating body and the friction member in the fourth embodiment. [Figure 16] 10A and 10B are diagrams showing the rotation direction and driving force of the vibration type motor of the fourth embodiment. [Figure 17] 10 is a diagram showing the contact area between the vibrating body and the friction member and the driving force in the vibration type motor of the fifth embodiment. [Figure 18] FIG. 13 is an exploded perspective view of an imaging device 600 according to a sixth embodiment. [Figure 19] FIG. 13 is a cross-sectional view of an imaging device 600 according to a sixth embodiment. [Figure 20] 4A and 4B are diagrams showing the relationship between the vibration of the vibrating body, the tilt angle between the vibrating body and the contact surface, and the generated driving force. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Example]

[0010] 2(A) to 2(D) show the appearance of a vibration motor 100 as a vibration actuator according to a first embodiment of the present invention. FIG. 2(A) is a perspective view of the vibration motor 100 as seen from the front (vibrator unit) side, and FIG. 2(B) is a perspective view of the vibration motor 100 as seen from the back. FIG. 2(C) is a plan view of the vibration motor 100 as seen from the front side, and FIG. 2(D) is a side view of the vibration motor 100. FIGS. 3(A) and 3(B) show an exploded view of the vibration motor 100. FIG. 1 shows a cross section (XY cross section) of the vibration motor 100 taken along line AA in FIG. 2(C).

[0011] The vibration type motor 100 has a base member 122 that serves as its base, a vibrating body unit held by the base member 122, and a friction member 121 that serves as a contact member. The vibrating body unit has a vibrating body 101 and a pressure mechanism. The friction member 121 is rotatable around a rotation center axis (first axis) P, and has a contact surface 121s that is parallel to a plane (within the XZ plane serving as the first plane) that is perpendicular to the rotation center axis P.

[0012] In this embodiment, the direction parallel to the rotation center axis P of the friction member 121 is defined as the Y direction, the longitudinal direction of the vibrating body 101 as the Z direction, and the direction perpendicular to the Y and Z directions as the X direction. The axis extending in the Z direction is defined as the Z axis. The contact surface 121s between the vibrating body unit and the friction member 121 is arranged in the Y direction. The direction in which the vibrating body 101 moves away from the contact surface 121s is defined as the +Y direction, and the direction in which the vibrating body 101 moves towards the friction member 121 is defined as the -Y direction. Note that "parallel" and "perpendicular" in this embodiment refer to a range that can be considered as parallel or perpendicular, including deviations from perfect parallel or perpendicular due to manufacturing errors and mechanical play in the vibration motor.

[0013] The vibrating body 101 is composed of an elastic body 102 and a piezoelectric element 103. The piezoelectric element 103 is made of PZT (lead zirconate titanate) or the like, and the elastic body 102 is formed as a stainless steel plate or the like. The elastic body 102 has two protrusions 102a and two held portions 102b in the Z direction. The tips of the two protrusions 102a form hemispherical (curved) surfaces 102c. The elastic body 102 and the piezoelectric element 103 are fixed with an adhesive. The friction member 121 is a disk-shaped member centered on the rotational axis P of the vibration motor 100 and has a contact surface 121s on its surface. The vibrating body 101 is pressurized in the -Y direction by a pressure mechanism, whereby the hemispherical surfaces 102c of the protrusions 102a come into pressure contact with contact points (contact positions) 102d on the contact surface 121s of the friction member 121.

[0014] The friction member 121 has a shaft portion 121a that is rotatably fitted into and held in a rotation support hole portion 122a provided in the base member 122. Between the rolling bearing portion 121b provided in the friction member 121 and the rolling bearing portion 122b provided in the base member 122, rolling balls 108 are arranged at multiple locations in the circumferential direction of the vibration-type motor 100.

[0015] The elastic body 102 is integrated with the first holding member 104, with its held portion 102b held by the first holding member 104. The first holding member 104 is held by a frame member 113 via an elastic connecting member 114. The frame member 113 is fixed with screws 115 to a chassis 122d fixed to a base member 122. As a result, the elastic body and first holding member 104 are positioned and fixed relative to the friction member 121.

[0016] The vibration motor 100 is provided with a blocking member 105. The blocking member 105 is a member that makes it difficult for vibrations of the piezoelectric element 103 to propagate to a small base 106 (described later). The blocking member 105 is made of felt fabric or the like.

[0017] The small base 106 is a pressure transmission member that comes into surface contact with the piezoelectric element 103 via the blocking member 105 and transmits pressure from a pressure mechanism (pressure member 110 described later) to the vibrating body 101. The pressure mechanism is held by a second holding member 107. The second holding member 107 is fixed to the chassis 122d together with the frame member 113 described above by screws 115.

[0018] The pressure mechanism is made up of a pressure member 110, a pressure spring 111, and a pressure receiving member 112. The pressure member (movable member) 110 is held by the pressure receiving member 112 so as to be movable only in the Y direction by fitting an engagement shaft portion 110a thereof into a fitting hole portion 112a of the pressure receiving member 112. The pressure receiving member 112 is fixed to the second holding member 107 by fastening a screw portion 112b formed on the outer circumferential surface thereof into a screw hole portion 107a of the second holding member 107.

[0019] The pressure spring 111 is a compression coil spring, one end of which is fixed to the pressure receiving member 112 and the other end of which abuts against the pressure member 110. The pressure member 110 transmits a pressure force F1 from the pressure spring 111, which is disposed between the pressure member 110 and the pressure receiving member 112, to the small base 106. The small base 106 transmits the pressure force F1 to the vibrating body 101 via the blocking member 105, causing the vibrating body 101 to come into pressure contact with the friction member 121. By setting the position at which the pressure mechanism applies the pressure force F1 to the vibrating body 101 to be approximately midway between the positions of the two protrusions 102a of the elastic body 102 in the Z direction, the two protrusions 102a can be brought into pressure contact with the friction member 121 in a balanced manner.

[0020] 1, in this embodiment, the vibrating body 101 is inclined at an angle θ1 with respect to the contact surface 121s of the friction member 121 from the Y direction parallel to the rotation center axis P. The reason for this will be described later.

[0021] The driving principle of the vibration motor 100 will be explained using Figures 4(a) to (c). Figures 4(a) and (b) schematically show the vibration modes of the vibrating body 101. Figure 4(c) shows a simplified cross section (YZ cross section) of the vibration motor 100 taken along line FF in Figure 2(c), and schematically shows the periphery of the protrusion 102a that performs elliptical motion indicated by arrow E, which will be described later.

[0022] When a frequency signal (AC voltage) is applied to the piezoelectric element 103, the piezoelectric element 103 expands and contracts, but the elastic body 102 does not expand and contract easily. This causes bending deformation in the vibrating body 101, which is made by bonding the piezoelectric element 103 and the elastic body 102 together. Therefore, when a high-frequency AC voltage is applied to the piezoelectric element 103, a high-frequency bending vibration mode can be generated in the vibrating body 101.

[0023] The vibration mode of the vibrating body 101 is a composite vibration including a first vibration and a second vibration. As shown in FIG. 4(a), the first vibration generates a reciprocating motion M1 indicated by the arrow in the protruding portion 102a of the vibrating body 101, displacing the protruding portion 102a mainly in the tangential direction of the contact surface 121s. The first vibration generates multiple nodes N1. The vibrating body 101 has three nodes N1 indicated by dashed lines, and the nodes N1 at both ends of the vibrating body 101 in the longitudinal direction are located near the protruding portion 102a.

[0024] 4(b), the second vibration generates a reciprocating motion M2 indicated by the arrow in the protrusion 102a, displacing the protrusion 102a mainly in the direction of contact with and separation from the contact surface 121s. The second vibration generates multiple nodes N2. The vibrating body 101 has two nodes N2 indicated by the dashed lines.

[0025] By generating the first vibration and the second vibration at the same frequency, it is possible to generate an elliptical motion indicated by an arrow E at the contact portion 102d of the protrusion 102a that contacts the contact surface 121s, as shown in Fig. 4(c). In the vibrating body 101, a plurality of (two) contact portions 102d are provided to generate a larger driving force, but only one may be provided.

[0026] When the hemispherical surface 102c of the protrusion 102a is in pressurized contact with the contact surface 121s of the friction member 121 by the pressure F1, an elliptical motion occurs in the protrusion 102a, and a driving force F2 is generated between the hemispherical surface 102c and the contact surface 121s, driving the friction member 121. In this embodiment, the friction member 121 is driven to rotate around the central rotation axis P shown in FIGS.

[0027] 3A and 3B, in this embodiment, the driving radius, which is the distance from the rotation axis P to the contact point 102d where the protrusion 102a comes into contact with the friction surface 121s, is Rd. The direction in which the driving force F2 is generated is the tangential direction (Z direction: first direction) of the tangent to a circle (a circle passing through point 102d) with a radius of Rd and centered on the rotation axis P. By changing the signs of the vibration phases of the two vibration modes described above, the direction of the elliptical motion of the protrusion 102a changes, and therefore the direction in which the driving force F2 is generated can be switched between the positive (+) direction and the negative (-) direction.

[0028] 5(A) and (B) will be used to explain the lateral slippage of the friction member 121 relative to the vibrating body 101 that occurs when the friction member 121 is rotationally driven in a conventional vibration type motor. Fig. 5(A) shows the conventional vibration type motor as viewed from the Y direction, and Fig. 5(B) shows a cross section (XY cross section) of the conventional vibration type motor taken along line BB in Fig. 5(A). Note that the same components of the conventional vibration type motor as those of the vibration type motor of this embodiment are designated by the same reference numerals as those of this embodiment.

[0029] In a conventional vibration motor, the vibrating body 101, which is disposed on an XZ plane perpendicular to the central axis of rotation P, is pressed against the friction member 121 from the Y direction parallel to the central axis of rotation P. As described above, the elliptical motion of the two protrusions 102a of the vibrating body 101 generates a driving force F2 in the tangential direction of the driving radius Rd (the direction within the plane of the elliptical motion of the protrusions 102a) centered on the central axis of rotation P, and the friction member 121 is rotated in the Q direction shown in FIG. 5(A). Point R shown in FIG. 5(A) is the generating center position of the driving force F2 generated by the elliptical motion of the two protrusions 102a, and is located on the friction surface 121s. For convenience of explanation, the arrow of the driving force F2 is not drawn starting from point R in FIG. 15(A), but in reality, it is a force generated in the Z-axis direction starting from point R.

[0030] However, the friction member 121, which is the driven part, is driven by rotation relative to the direction in which the driving force F2 is generated (linear direction), and because the direction in which the driving force is generated and the direction in which the driven part is driven are different, a loss of driving force occurs by the difference between these directions. The loss of driving force occurs when the protrusion 102a slides sideways on the contact surface 121s of the friction member 121 when transmitting the driving force due to elliptical motion to the contact surface 121s. Specifically, when the friction member 121 is driven to rotate by Δθt due to the driving force ΔF2 generated per unit time Δt, the movement trajectory of point R of the friction member 121 is the arc-shaped line segment R_t shown in Figure 5.

[0031] On the other hand, if the driving direction of the driven member 121 is the Z direction, which is the same as the driving force generation direction, the movement locus of point R will be the line segment Z_t shown in Figure 5. The difference D_t between R_t and Z_t is the loss of driving force, and generates a sideslip component ΔDx_t in the X direction as shown in Figure 5(B). The sideslip component ΔDx_t occurs because there is a difference between the driving force generation direction and the driving direction of the driven member. The smaller the driving radius Rd, the larger the sideslip component ΔDx_t. However, the larger Rd, the smaller the sideslip component ΔDx_t, as the rotational drive of the driven member approaches linear drive. This sideslip component ΔDx_t causes the protrusion 102a to slide excessively against the friction member 121, accelerating wear.

[0032] 6(A) to 6(D) show vibration motors that do not cause skidding due to loss of driving force as described above. These vibration motors are disclosed in Japanese Patent Application Laid-Open No. 2019-126211, which was previously filed by the applicant.

[0033] Fig. 6(A) shows an outer peripheral arrangement type vibration motor in which the vibrator unit 101 is arranged on the outer periphery of the friction member 221, as viewed from the Y direction, and Fig. 6(B) shows a cross section of the outer peripheral arrangement type vibration motor when cut along line CC in Fig. 6(A). Fig. 6(C) shows the outer peripheral arrangement type vibration motor when viewed from the X direction. Fig. 6(D) shows an inner peripheral arrangement type vibration motor in which the vibrator unit 101 is arranged on the inner periphery of the annular friction member 321, as viewed from the Y direction, and Fig. 6(E) shows a cross section of the inner peripheral arrangement type vibration motor when cut along line DD in Fig. 6(D).

[0034] 6(A) to 6(C), the vibrating body 101 is pressed from the radially outer side of the friction member 221 by a pressure force F1, and the protrusion 102a of the vibrating body 101 is brought into pressure contact at point 102d with the friction surface 221s, which is the outer peripheral surface of the friction member 221. This generates a driving force F3 in the Z direction as shown in FIG.

[0035] 6(D) and (E), the vibration motor of the inner peripheral arrangement type is configured such that the vibration body 101 is pressed from the radially inner side of the friction member 321 by a pressure force F1, and the protrusion 102a of the vibration body 101 is brought into pressure contact at point 102d with the friction surface 321s, which is the inner peripheral surface of the friction member 321. This generates a driving force in the Z direction, similar to the outer peripheral arrangement type shown in FIG.

[0036] In these vibration type motors, the friction members 221, 321 rotate around the rotation center axis P by a driving force generated in the Z direction, similar to the friction member 121 of this embodiment. At this time, the friction members 221, 321 rotate without skidding relative to the protrusion 102a of the vibrating body 101, which is moving in an elliptical motion, and all of the generated driving force serves to rotationally drive the friction members 221, 321.

[0037] However, in an outer peripheral arrangement type vibration motor, the pressure mechanism for applying pressure to the vibrating body 101 against the friction member 221 from the radial outside is arranged further radially outward than the vibrating body 101, which increases the outer diameter of the vibration motor. Also, in an inner peripheral arrangement type vibration motor, the pressure mechanism is arranged further radially inward than the vibrating body 101, which requires a friction member with a large inner diameter, which increases the outer diameter of the vibration motor.

[0038] In this embodiment, the lateral slip of the friction member relative to the vibrating body is reduced without disposing the vibrating body on the outer or inner periphery of the friction member as in the vibration-type motors of Figures 6(A) to 6(E). Specifically, the vibrating body 101 is disposed tilted about an axis parallel to the direction in which the driving force is generated relative to the contact surface 121s of the friction member 121.

[0039] 7(A) to 7(D) show examples of the relationship between the vibrating body 101 and the friction surface 121s in this embodiment in cross sections similar to those in Fig. 5(B). In all of the examples in Fig. 7(A) to 7(D), when the vibrating body 101 is brought into pressure contact with the friction surface 121s by the application of pressure F1, a driving force is generated in the Z direction, which is perpendicular to the plane of the drawing, at the contact point 102d.

[0040] In the examples of Figures 7(A) and (B), the vibrating body 101 is tilted by an angle θ around an axis parallel to the Z axis with respect to the friction surface 121s, which is parallel to the XZ plane. In the examples of Figures 7(C) and (D), the friction surface 121s is tilted by an angle θ around an axis parallel to the Z axis with respect to the vibrating body 101, which is arranged parallel to the XZ plane. As a result, compared to the relationship between the vibrating body 101 and the friction surface 121s shown in Figure 5(B), the examples of Figures 7(A) and (D) are closer to the outer peripheral arrangement type shown in Figure 6(B), and the examples of Figures 7(B) and (C) are closer to the inner peripheral surface arrangement type shown in Figure 6(E). This makes it possible to reduce the drive loss D_t that occurred in Figures 5(A) and (B), that is, to reduce the sideslip component ΔDt_x.

[0041] However, the inclination angle θ must be set under the condition that the pressure force F1 causes the two protrusions 102a to be in stable pressure contact with the friction surface 121s, and that the hemispherical surface 102c of the protrusions 102a contacts the friction surface 121s only at point 102d.

[0042] Using Figures 20(A) to (F), the relationship between the tilt angle θ, the elliptical motion of the protrusion 102a due to the vibration mode of the vibrating body 101 shown in Figure 4(C), and the driving force generated by the vibration motor 100 will be described. Figures 20(A) to (F) show the relationship between the vibration of the vibrating body, the tilt angle θ between the vibrating body and the contact surface, and the driving force generated. Figures 20(A) to (C) show the above relationship in a conventional vibration motor in which the tilt angle θ is zero. Figures 20(D) to (F) show the above relationship in the case where the vibrating body 101 is arranged tilted by θ around an axis parallel to the driving force generation direction, as in the vibration motor 100 of this embodiment. Figure 20(B) shows Figure 20(A) as viewed from the Z-axis direction, and Figure 20(E) shows Figure 20(D) as viewed from the Z-axis direction.

[0043] 20(A) and (D) are schematic diagrams showing one of the protrusions 102a of the elastic body 102 shown in Fig. 4(C), and the driving force is generated in the Z-axis direction, which is the left-right direction in the figure. Fig. 20(C) and (F) are diagrams seen from the Z-axis direction, the same as Fig. 20(B) and (E), and show the relationship between the force generated at point 102d where the vibrating body 101 abuts against friction surface 121s due to pressure force F1 applied to the vibrating body 101.

[0044] In the conventional vibration motor shown in Figure 20(A), the protrusion 102a abuts against the friction surface 121s at point 102d and moves in an elliptical motion indicated by arrow E, causing the protrusion 102a to generate a driving force of ΔF2_1 per unit time in the Z-axis direction. In contrast, in the vibration motor of this embodiment shown in Figure 20(D), the vibrating body 101 is disposed at an angle θ around the Z' axis, which is parallel to the Z-axis, and the protrusion 102a' abuts against the friction surface 121s at point 102d'. As a result, the elliptical motion indicated by arrow E' generates a driving force of ΔF2_1' per unit time in the Z-axis direction.

[0045] The elliptical motion indicated by arrow E and the elliptical motion indicated by arrow E'1 both generate driving forces only in the Z-axis direction at the contact portions 102d and 102d', so the tilt angle θ does not result in driving loss when generating driving forces due to the elliptical motion of the protrusion 102a'. In other words, ΔF2_1 = ΔF2_1'.

[0046] However, if the force F1s' that the contact portion 102d' receives perpendicularly from the friction surface 121s is smaller than the pressure force F1 due to the inclination angle θ, the force with which the protrusion 102a kicks the friction surface 121s due to the elliptical motion will be smaller, and the driving force will be smaller. As shown in Figure 20(C), when a pressure force of F1 is applied to the vibrating body 101, if the vibrating body 101 and the friction surface 121s are parallel, the force F1s that the contact portion 102d receives perpendicularly from the friction surface 121s will be equal to F1.

[0047] 20(F), when the pressure force F1 is also rotated by θ around an axis parallel to the Z axis, the pressure force F1 is split into F1s_y in the Y-axis direction and F1s_x in the X-axis direction at the contact portion 102d'. At this time, the force F1s' that the contact portion 102d' receives perpendicularly from the friction surface 121s is equal to F1s_y, F1s_y=F1×cosθ Therefore, F1s' <F1 That is, the force with which the protrusion 102a' kicks the friction surface 121s decreases depending on the tilt angle θ, and the driving force decreases. To avoid this decrease in driving force, it is necessary to set the pressure force F1 large in accordance with the tilt angle θ so that F1s' has the necessary magnitude.

[0048] Furthermore, the force F1s_x acting in the X-axis direction at the contact portion 102d' is expressed as follows: F1s_x=F1×sinθ Therefore, it increases as the tilt angle θ increases. If the friction coefficient between the protrusion 102a and the friction surface 121s is μ and the normal resistance is N (= F1s'), when F1s_x exceeds μ×N, the contact portion 102d' slides against the friction surface 121s and is unable to generate a driving force.

[0049] Therefore, as described above, the tilt angle θ can reduce the sideslip component ΔDt_x, but it can also reduce the force that the contact portion 102d' receives perpendicularly from the friction surface 121s, potentially reducing the driving force. Furthermore, if θ is too large, the contact portion 102d' may slip on the friction surface 121s, preventing the generation of driving force. In these cases, the pressure force F1 can be set to be large enough to compensate for the reduction in the force that the contact portion 102d' receives perpendicularly from the friction surface 121s, and the tilt angle θ can be set within a range in which the contact portion 102d' does not slip on the friction surface 121s and stably contacts the friction surface 121s.

[0050] 1, in this embodiment, as shown in Fig. 7(A), the vibrating body 101 is tilted by an angle θ1 radially outward (clockwise) from the friction surface 121s of the friction member 121. The tilt of the vibrating body 101 refers to the tilt of the flat portion of the vibrating body 101 (elastic body 102) on which the protrusions 102a are provided.

[0051] 1, the axis parallel to the Z axis, which is the direction in which the driving force is generated, and passing through point 102d where protrusion 102a contacts friction surface 121s, is defined as T (second axis). Also, the line passing through point 102d and parallel to rotation center axis P (i.e., perpendicular to friction surface 121s) is defined as S.

[0052] In this embodiment, the vibrating body 101 is held in a position tilted about an axis T at an angle θ1 with respect to the line S, so that the vibrating body 101 is tilted at the same angle with respect to the contact surface 121s of the friction member 121. This position can be maintained by making the thickness in the Y direction of the radially outer portion of the frame member (positioning member) 113 that holds the vibrating body 101 via the first holding member 104 smaller than the thickness of the radially inner portion, and by making the first holding member 104 form an angle θ1 with respect to the chassis 122d. A second holding member 107 that holds a pressure mechanism is fixed to the frame member 113. Therefore, the vibrating body unit, which is made up of the vibrating body 101 and the pressure mechanism, is integrally tilted by the angle θ1 around the axis T with respect to the friction member 121 that is rotatably held on the base member 122.

[0053] According to this embodiment, by arranging the vibrating body 101 at an angle with respect to the contact surface 121s of the friction member 121, it is possible to realize a configuration that reduces lateral slippage of the friction member 121 relative to the vibrating body 101 while avoiding an increase in size in the radial direction. This reduces loss of driving force and wear of the vibrating body 101, and suppresses the generation of wear powder.

[0054] 7B, the vibrating body 101 may be tilted radially inward (counterclockwise) relative to the friction member 121. In this case, the effect of suppressing sideslip is the same. However, in order to make it difficult for wear debris to adhere to the rolling balls 108 and around the shaft portion 121a when wear debris is generated, it is preferable to tilt the vibrating body 101 radially outward (clockwise) relative to the friction member 121 as in this embodiment. [Example]

[0055] Next, a vibration type motor 200 according to a second embodiment of the present invention will be described. In the second embodiment, the configuration shown in Fig. 7(A) is adopted as in the first embodiment, but the configuration is realized in a different method from that of the first embodiment. In the second embodiment, a description of the parts common to the first embodiment will be omitted.

[0056] In Example 1, the vibrating body unit was arranged tilted by an angle θ1 around the axis T with respect to the friction member 121. In contrast, in Example 2, a small base 106, which is part of the pressure mechanism, is used to tilt only the vibrating body 101 by an angle θ2 around the axis T.

[0057] The small base 106 in this embodiment will be described with reference to Figures 8 and 9. The small base 106 shown in Figure 8 has two protrusions (contact portions) 106a and 106b that have a thickness (height) in the Y direction. Figure 9 shows a cross section of the vibration motor 200 corresponding to the cross section taken along line FF in Figure 2(C), and Figure 10 shows a cross section of the vibration motor 200 corresponding to the cross section taken along line AA in Figure 2(C).

[0058] As described in Example 1, the small base 106 is a pressure transmission member that transmits the pressing force F1 from the pressing member 110 to the vibrating body 101. The transmission path of the pressing force F1 is as follows. In FIG. 9, a pressing spring 111 (not shown) abuts on the pressing member 110, and the pressing member 110 abuts on the convex portions 106a and 106b of the small base 106. The small base 106 is in surface contact with the piezoelectric element 103 via the blocking member 105. Through such a transmission path, the pressing force F1 generated by the pressing spring 111 is transmitted to the vibrating body 101.

[0059] At this time, the small base 106 has a degree of freedom of rotation in the direction of arrow R in FIG. 9 (around an axis parallel to the X-axis) with respect to the pressing member 110 by abutting on the pressing member 110 at the convex portions 106a and 106b. This is to uniformly apply the pressing force F1 to the entire vibrating body 101 via the small base 106, and to smoothly rotationally drive the friction member 121 by transmitting the elliptical motion of the vibrating body 101 to the friction surface 121s at the two points 102d. Unnecessary vibrations other than the elliptical motion, and play due to component tolerances and assembly variations, etc. are absorbed by the rotational freedom of the small base 106 in the direction of arrow R.

[0060] In this embodiment, as shown in FIG. 10, the small base 106 is used as the positioning member. Specifically, the thickness a of the convex portion 106a and the thickness b of the convex portion 106b in the Y direction are made different from each other. In this embodiment, a < b. As a result, similarly to Example 1, the vibrating body 101 can be held in a posture inclined by an angle θ2 with respect to the contact surface 121s around an axis T parallel to the Z direction, which is the direction of generation of the driving force. However, unlike Example 1, the pressing mechanism is not inclined. Even if the heights a and b of the convex portions 106a are different, the degree of freedom of the small base 106 in the direction of arrow R described above is maintained.

[0061] In this embodiment, by simply changing the height of one of the convex portions 106a and 106b of the small base 106, the inclination angle of the vibrating body 101 with respect to the friction surface 121s can be set, and the inclination angle can be adjusted more easily than in Example 1.

Example

[0062] Next, a vibration type motor 300 according to a third embodiment of the present invention will be described. In the third embodiment, the shape of the friction member 121 is different from that in the first embodiment, and the configuration shown in Fig. 7(D) is adopted. In the third embodiment, the description of the parts common to the first embodiment will be omitted.

[0063] FIG. 11 shows a cross section of the vibration motor 300 corresponding to the cross section taken along line AA in FIG. 2(C). In this embodiment, the vibrating body 101 is held in a position parallel to the XZ plane. Meanwhile, the friction member 121 is formed so that the friction surface 121s with which the protrusion 102a of the vibrating body 101 comes into contact is not perpendicular to the rotation center axis P but is tilted radially inward by an angle θ3. In other words, the friction surface 121s is an inclined surface like a bank. By using a friction member 121 with such a shape, the vibrating body 101 is tilted by an angle θ3 around the axis T with respect to the friction surface 121s, and the configuration shown in FIG. 7(D) is realized.

[0064] The friction surface 121s may be inclined radially outward as shown in FIG. 7(C). However, in order to prevent wear debris from adhering to the rolling ball 108 and the shaft portion 121a, it is preferable to incline the friction surface 121s radially inward as in this embodiment.

[0065] Furthermore, in each of the above embodiments, the case where only one of the vibrating body 101 and the contact surface 121s is inclined with respect to the XZ plane has been described, but both of them may be inclined in opposite directions with respect to the XZ plane. [Example]

[0066] Next, a vibration type motor 400 according to a fourth embodiment of the present invention will be described. The vibration type motor 400 has a configuration in which the posture of the vibrating body 101 is changed compared to the vibration type motor 100 according to the first embodiment, which employs the configuration shown in Fig. 7(A). In this embodiment, a description of the parts common to the vibration type motor 100 will be omitted.

[0067] 12 shows the detailed shape of vibrating body 401 in Example 4. Vibrating body 401 is composed of piezoelectric element 403 and elastic body 402. Elastic body 402 has two protrusions 402a (first protrusion 402a1 and second protrusion 402a2). The tip of protrusion 402a1 and the tip of protrusion 402a2 are formed as hemispherical surfaces (curved surfaces) 402e1 and 402e2, respectively.

[0068] The elastic body 402 has held portions 402b on both ends thereof. Similar to the held portion 102b in the first embodiment, the held portions 402b are held by a first holding member (not shown) and are integrated with the first holding member.

[0069] Next, the attitude of the vibrating body 401 relative to the friction member 421 in the vibration type motor 400 and the contact area of ​​the vibrating body 401 that comes into contact with the friction member 421 will be described.

[0070] Figures 13(1a) and (1b) show the orientation of the vibrating body 101 relative to the friction member 121 in a conventional vibration motor 100 that does not suppress lateral slippage of the friction member 121 relative to the vibrating body 101. Figures 13(2a) and (2b) show the orientation of the vibrating body 101 relative to the friction member 121 in a vibration motor 100 of Example 1 that suppresses lateral slippage of the friction member 121 relative to the vibrating body 101. Figures 13(3a) and (3b) show the orientation of the vibrating body 401 relative to the friction member 421 in a vibration motor 400 of this example. Figures 13(1a), (2a), and (3a) show each vibrating body as viewed from the Y direction, and Figures 13(1b), (2b), and (3b) show each vibrating body and each friction member as viewed from the Z direction.

[0071] The vibrating body 101 of the vibration type motor 100 of Example 1 shown in Figures 13(2a) and (2b) has an attitude that is tilted by θ1 from the conventional attitude shown in Figures 13(1a) and (1b) with respect to a line S that passes through the contact point 102d on the contact surface 121s of the friction member 121 and is perpendicular to the friction surface 121s.

[0072] 13(3a) and (3b), the vibrating body 401 of the vibration motor 400 of this embodiment is rotated by θ4 around a straight line U in the tangent direction (Z direction) of a circle centered on the central axis of rotation P, relative to the vibrating body 101 of the first embodiment shown in Figures 13(2a) and (2b). The straight line U passes through the same point R as in Figure 5(A) and is perpendicular to the contact surface 121s (421s) of the friction member 121 (421).

[0073] 14 shows a contact area 121d where the two protrusions 102a (hemispherical surfaces 102c) of the vibrating body 101 of the vibration motor 100 of Example 1 come into contact with the contact surface 121s of the friction member 121 when viewed from the Y direction. The contact area 121d shows the contact area when the friction member 121 is rotatable 360 ​​degrees. Note that in the initial stage of driving the vibration motor 100, the protrusions 102a come into point contact with the contact surface 121s at the contact point 102d, resulting in a circular linear contact area w0.

[0074] 14(A) and 14(B) are the same as the point R shown in FIG. 5(A), and are the center of the driving force F2 generated by the two protrusions 102a of the vibrating body 101.

[0075] 14, in the vibration motor 100 of the first embodiment, the vibrating body 101 has its two protrusions 102a aligned in the tangent direction (Z direction) of a circle of radius Rd centered on the central axis of rotation P. Therefore, the two protrusions 102a contact the contact surface 121s at the same contact area 121d. Therefore, when the vibration motor 100 is driven, the two protrusions 102a wear the same contact area 121d on the contact surface 121s. 15 shows contact areas 421d1 and 421d2 where two protrusions 402a1 and 402a2 (hemispherical surfaces 402e1 and 402e2) of the vibrating body 401 in the vibration motor 400 of this embodiment come into contact with the contact surface 421s of the friction member 421 in the vibration motor 400 of this embodiment as seen from the Y direction. As described above, in the vibration motor 400 of this embodiment, the vibrating body 401 has an attitude rotated around the straight line U at an angle θ4 with respect to the Z direction, which is the tangent direction of a circle centered on the central axis of rotation P of the friction member 121.

[0076] At this time, the direction in which protrusions 402a1 and 402a2 are aligned forms an angle θ4 with the Z direction, which is a first direction in which a tangent to a circle centered on rotation axis P extends. Vibration body 401 is tilted with respect to contact surface 421s around a second axis parallel to this first direction. Due to this posture of vibration body 401, the distance from rotation axis P to protrusion 402a1 and the distance from protrusion 402a2 to vibration body 401 tilted with respect to contact surface 421s become different from each other. As a result, as shown in FIG. 15 , protrusions 402a1 and 402a2 of vibration body 401 come into contact with contact surface 421s of friction member 421 at different contact regions 421d1 and 421d2.

[0077] The contact area 421d1 with which the protrusion 402a1 comes into contact and the contact area 421d2 with which the protrusion 421d2 comes into contact become circular band-shaped areas having widths d2 and d3, respectively, by driving the vibration motor 400 for a long period of time. In this way, in the vibration motor 400, the two protrusions 402a1 and 402a2 come into contact with the contact surface 421s at different contact areas 421d1 and 421d2, so the progress of wear of the vibrating body 401 and the friction member 421 is reduced (roughly halved) compared to the vibration motor 100 of the first embodiment. As a result, the life of the vibration motor 400 can be extended compared to the vibration motor 100 of the first embodiment, and the generation of wear powder can also be reduced.

[0078] However, in the vibration motor 400 of this embodiment, the direction of the driving force generated in the tangential direction changes by the amount of rotation of the vibrating body 401 by θ4 relative to the vibrating body 101 of Example 1, which may result in a lower driving efficiency than the vibration motor 100 of Example 1. Specifically, when θ4 is 0 degrees (no rotation), the driving force is generated in the tangential direction (Z direction) of the radius Rd centered on the P axis, and the force acting around the rotation axis is the radius × tangential force. Therefore, the efficiency of the force for rotation around the P axis at this time is 100%. However, when θ4 is 90 degrees, the driving force is generated in the direction perpendicular to the tangent (X direction), and since there is no tangential component, rotation around the P axis is not possible. In other words, as θ4 approaches 90 degrees, the tangential driving force required for rotation cannot be obtained, and the rotational force for rotating the driven member becomes weaker.

[0079] Furthermore, the effect differs depending on the rotation direction of the vibration motor 400. Figure 16 shows the rotation direction and driving force of the vibration motor 400 of this embodiment. The direction in which the friction member 421 rotates counterclockwise is designated as Qa, and the direction in which it rotates clockwise is designated as Qb.

[0080] 16, when a voltage is applied to the piezoelectric element 403 when the rotation direction of the friction member 421 is Qa, a driving force is generated in the direction (first direction) in which the protrusions 402a1 and 402a2 of the vibrating body 401 are aligned, similar to the vibration-type motor 100 of the first embodiment. The driving force ΔF4a per unit time at this time is decomposed into ΔF4a_z in the Z direction parallel to the tangent line R2 and ΔF4a_x in the X direction perpendicular to the Z direction. ΔF4a_z is ΔF4×cos θ4, and is therefore smaller than ΔF4a. In other words, by rotating the vibrating body 401 by θ4, the driving force component used to rotationally drive the friction member 421 is reduced. Furthermore, ΔF4a_x in the X direction is ΔF4a×sin θ4, which is the −X direction toward the rotation center axis P.

[0081] On the other hand, when the rotation direction of the friction member 421 is Qb, a driving force is generated in the direction in which the protrusions 402a1 and 402a2 of the vibration body 401 are aligned, which is the opposite direction to when the rotation direction is Qa. The driving force ΔF4b per unit time at this time is decomposed into ΔF4b_z in the Z direction and ΔF4b_x in the X direction. ΔF4b_z is ΔF4×cos θ4, and is therefore smaller than ΔF4b. In other words, by rotating the vibration body 401 by θ4, the driving force component used to rotationally drive the friction member 421 is reduced. Furthermore, ΔF4b_x in the X direction is ΔF4b×sin θ4, but its direction is the +X direction away from the rotation center axis P. Thus, when ΔF4a and ΔF4b are equal in magnitude, the magnitudes of the driving force components resolved into the Z and X directions are equal regardless of the rotation direction Qa or Qb. However, the direction in which the driving force component in the X direction acts differs depending on the rotation direction Qa or Qb. When the rotation direction is Qa, the driving force component acts in the -X direction, so the friction member 421 rotates while receiving a force in the -X direction. On the other hand, when the rotation direction is Qb, the driving force component acts in the +X direction, so the friction member 421 rotates while receiving a force in the +X direction. In this case, if there is a gap between the driven part and the driving part, such as backlash, the direction in which the gap closes differs depending on the rotation direction, so the magnitude of the driving force required for rotational drive may vary depending on the rotation direction. If it is expected that the magnitude of the driving force will vary depending on the rotation direction, the control unit that controls the drive of the vibration-type motor 400 can control the driving force using control parameters that differ depending on the rotation direction.

[0082] 15, angle θ4 may be any angle that prevents hemispherical surface 402e1 of protrusion 402a1 and hemispherical surface 402e2 of protrusion 402a2, projected onto the XZ plane, from lining up on the tangent of a circle centered on rotation central axis P. However, since the driving force in the tangential direction required for rotational drive decreases as angle θ4 increases, it is desirable to set angle θ4 appropriately in relation to the required driving force. [Example]

[0083] 17 shows a vibration type motor 500 of Example 5, which is an application of the vibration type motor 400 of Example 4. Example 5 has a configuration that reduces the difference in the driving force component in the X direction depending on the rotation direction described in Example 4. In this example, a description of parts common to the vibration type motor 400 of Example 4 will be omitted.

[0084] FIG. 17 also shows the contact area on the contact surface 521s of the friction member 521 of the first vibrating body 501 and the second vibrating body 701 provided in the vibration type motor 500 of this embodiment, and the driving force generated by the first and second vibrating bodies 501, 701.

[0085] The first and second oscillators 501 and 701 are disposed on opposite sides of the rotation center axis P when viewed from the Y direction, and both have the same shape and the same attitude relative to the friction member 521 as the oscillator 401 in Example 4. The rotation angle of the first and second oscillators 501 and 701 in this example around the axis corresponding to the axis U described in Example 4 is θ5.

[0086] The rotational driving range of the friction member 521 of the vibration type motor 500 is ±180 degrees. The protrusion 502a1 of the first vibrating body 501 contacts the contact surface 521s at a contact area 521d4, and the protrusion 502a2 contacts the contact surface 521s at a contact area 521d7. The protrusion 702a1 of the second vibrating body 701 contacts the contact surface 521s at a contact area 521d5, and the protrusion 702a2 contacts the contact surface 521s at a contact area 521d6. ​​These four contact areas do not overlap with each other within the rotational driving range of the friction member 521. Therefore, the vibration type motor 500 of this embodiment has a configuration that is less susceptible to wear, similar to the vibration type motor 400 of the fourth embodiment, compared to the vibration type motor 100 of the first embodiment in which the contact areas of the two protrusions overlap.

[0087] Furthermore, when the rotation direction of friction member 521 is Qb, vibrating body 501 generates a driving force of ΔF5 per unit time. ΔF5 is resolved into ΔF5_z in the Z direction parallel to the tangent direction of a circle centered on rotation central axis P, and ΔF5_x in the X direction perpendicular to the Z direction. ΔF5_x acts in the -X direction.

[0088] On the other hand, when the rotation direction of the friction member 521 is Qb, the oscillator 701 generates a driving force of ΔF7 per unit time in the opposite direction to the oscillator 501. ΔF7 is resolved into ΔF7_z in the Z direction and ΔF7_x in the ZX direction, with ΔF7_x acting in the +X direction. For smooth rotational driving, it is desirable that the driving forces generated by the two oscillators 501, 701 are equal, that is, ΔF7 and ΔF5 are equal. In this case, ΔF5_x and ΔF7_x have the same magnitude but act in opposite directions, so they cancel each other out. This is also true when the rotation direction is opposite to Qb.

[0089] In this embodiment, the vibration motor 500 is configured so that the contact areas where the two protrusions of each of the multiple vibrating bodies contact the friction member are different (do not overlap), and the driving force components that are not used for rotational driving among the driving forces generated by each vibrating body are canceled out. This configuration suppresses the above-mentioned sideslip, further reduces the progression of wear, and enables smooth rotational driving regardless of the rotation direction.

[0090] The configurations of the vibration type motors 400 and 500 described in the fourth and fifth embodiments can be applied not only to the vibration type motor 100 of the first embodiment but also to the vibration type motor 20 of the second embodiment.

[0091] When the vibration type motor of each embodiment is implemented as a rotation drive device for various devices such as an imaging device, the base member 122 is fixed to the device body, and a driven member that rotationally drives the friction member 121 is connected to it. However, the friction member 121 may be fixed to the device body, and the base member 122 may be connected to the driven member. In other words, the vibration body 101 and the friction member 121 may rotate relative to each other to rotationally drive the driven member. The various devices include, in addition to imaging devices, laser light irradiation devices, robot arms, etc. [Example]

[0092] Next, an imaging device 600 according to a sixth embodiment of the present invention will be described with reference to Figures 18 and 19. Figure 18 is an exploded perspective view of the imaging device 600, and Figure 19 is a cross-sectional view of the imaging device 600 taken along an XY plane passing through a rotation center axis P1, which will be described later.

[0093] The imaging device 600 has an imaging unit 637 equipped with a lens barrel 638 mounted on the friction member 121, which is the driven part of the vibration type motor 100 of the first embodiment. Therefore, a description of parts common to the vibration type motor 100 will be omitted. The imaging unit 637 is rotatable around a rotation center axis P1 relative to a base member 622 that holds a vibrating body 601, which will be described later. Note that the vibration type motors 200, 300, 400, and 500 of the second to fifth embodiments may be used instead of the vibration type motor 100 of the first embodiment.

[0094] Imaging unit 637, which is the driven part of imaging device 600, supports holding frame 639, which holds lens barrel 638, internally, and is fixed to connecting member 635 by fastening screws 636. Furthermore, connecting member 645 is fixed to friction member 630 by fastening screws 630. Friction member 630 holds scale 633 for position detection. Scale 633 has a texture engraved radially at regular intervals on the surface facing position detection sensor 632, which will be described later. Position detection sensor 632 can calculate the amount of rotation of the driven part by sequentially reading and integrating the texture of scale 633.

[0095] Next, the configuration of the fixed side relative to the driven part will be described. The fixed side mainly includes the area around the position detection sensor 632 described above, the area around the vibrating body 601 that generates the driving force, and the electronic board 640 described below, all of which are fixed to the base member 422.

[0096] The position detection sensor 632 is held by a sensor holding frame 631, and is fixed to the chassis 622d via a pressing member 623 at a position opposite the scale 633. The chassis 622d is fixed to the base member 622 by fastening screws 630.

[0097] The electronic board 640 is equipped with a microcomputer and the like for processing signals from the position detection sensor 632 and controlling the rotational drive of the driven parts.

[0098] The vibrating body 601 is a plate-shaped elastic body having two protrusions 602a. body The vibration motor 622 is made up of a vibration element 602 and a piezoelectric element 603, and is held by a chassis 622d via a frame member (not shown) in the same manner as the vibration motor 100. Furthermore, the vibration element 601 is pressed in the -Y axis direction by a pressure mechanism (not shown), and is in pressure contact with a friction surface 612s of the friction member 612. At this time, the friction surface 612s is formed on the friction member 612 in an attitude that forms an angle of θ6 around an axis parallel to the Z axis with respect to the vibration element 601. Furthermore, a bearing portion 634 is provided between the base member 622 and a connecting member 635, which is a driven part.

[0099] With the above configuration, when an AC voltage is applied to the piezoelectric element 603, a driving force is generated between the protrusion 602a and the friction surface 612s, and the imaging unit 637 fixed to the friction member 612 is rotated around the rotation center axis P1.

[0100] As described above, an angle of θ6 is formed between the vibrating body 601 and the friction surface 612s around an axis parallel to the Z axis, and the configuration shown in Fig. 7(D) is adopted. Therefore, similar to Examples 1 to 5, this has the effect of suppressing side slip caused by rotational driving, reducing drive force loss and wear of the vibrating body 601.

[0101] Although the friction surface 612s may be inclined radially outward as shown in FIG. 7(C), in order to prevent wear powder from adhering to the scale 633 and the position detection sensor 632 used to detect the position of the driven part, it is preferable to incline the friction surface 612s radially inward as in this embodiment.

[0102] The embodiments described above are merely representative examples, and various modifications and alterations are possible to each embodiment when implementing the present invention. [Explanation of symbols]

[0103] 100, 200, 300, 400, 500 vibration motor 101 Vibration body 102 Elastic Body 102a Protrusion 103 Piezoelectric element 121 Friction materials 121s contact surface F1 pressure force F2 driving force

Claims

1. A vibration type actuator comprising a vibrating body having a plate portion and an elastic body with a protrusion portion protruding outside the surface of the plate portion, the vibrating body being excited to vibrate by a piezoelectric element, and a contact member having a contact surface with which the protrusion portion comes into contact, which rotate relatively to each other around a first axis, a positioning member for holding the vibrator in a position inclined at a predetermined angle with respect to the contact surface, the contact surface is flat; the vibration body and the contact surface are arranged in a direction parallel to the first axis, The vibration actuator is characterized in that the thickness of the positioning member in a cross section along the first axial direction differs between a center side and an outer periphery side of the first axis.

2. The vibration device further includes a pressure mechanism for applying pressure to the vibration body against the contact surface, 2. The vibration actuator according to claim 1, wherein the direction of pressure applied by the pressure mechanism is inclined in the same direction as the inclination of the vibrating body.

3. A vibration type actuator as described in Claim 2, characterized in that the direction of pressure applied by the pressure mechanism is inclined at the same angle as the inclination of the vibrating body.

4. Further comprising a pressure mechanism for pressurizing the vibrator against the contact surface, the positioning member is a pressure transmission member that receives a pressure from the pressure mechanism and transmits the pressure to the vibrating body, the pressure mechanism has a movable member that is movable by the pressure, the positioning member has two contact portions that contact the movable member, 2. The vibration actuator according to claim 1, wherein the two contact portions have different thicknesses in cross section along the first axial direction.

5. The attitude determining member is a frame member that holds the vibrating body via a first holding member that holds the elastic body, 2. The vibration actuator according to claim 1, wherein the positioning member has a cross-sectional shape along the first axial direction, the thickness of which differs between a center side and an outer periphery side of the first axis.

6. 6. The vibration actuator according to claim 1, wherein the protrusion has a curved surface, and the curved surface comes into contact with the contact surface at a point.

7. The vibrating body is the protrusions include a first protrusion and a second protrusion that are arranged in a first direction in which a tangent to a circle centered on the first axis extends, 7. A vibration actuator according to claim 1, wherein the distance from the first axis to the first protrusion and the distance from the first axis to the second protrusion are different from each other when viewed from the direction in which the first axis extends.

8. The vibrating body includes a first vibrating body and a second vibrating body each having a first protrusion and a second protrusion, 8. The vibration actuator according to claim 7, wherein the first vibrating body and the second vibrating body are arranged so that the contact areas on the contact surfaces where the first and second protrusions contact each other do not overlap each other.

9. The vibration type actuator according to any one of claims 1 to 8, and a driven member that is rotationally driven by the vibration type actuator.

10. The rotary drive device according to claim 9 ; an imaging unit as the driven member;

Images